• 한국수소및신에너지학회논문집
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• 제5권2호
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• pp.81-90
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• 1994

The hydrogen fuel tanks having hydrogen storing capacity of about 300g and 1200g are manufactured using $MmNi_{4.7}Al_{0.25}V_{0.05}Fe_{0.001}$ alloy. They are composed of several unit reactor made of Cu-tube(outer diameter = 50.1mm, thickness = 2mm). In order to increase the heat and mass transfer property of the hydride bed, Al-plates are inserted perpendicular to axial direction at intervals of 5mm and three arteries of diameter 8mm are installed symmetrically in each unit reactor. Hydrogen absorption is proceeded about 80% within 30 minute and is completed within 60 minute at the conditions of charging hydrogen pressure of 25atm and temperature of $22^{\circ}C$. On desorbing hydrogen at a constant rate of 30 slm at $20^{\circ}C$, discharging hydrogen pressure is sustained at 3~5atm for 120 minutes. The discharging pressure is increased upto 5~8atm as the increase of the reactor temperature to $30^{\circ}C$. From the experimental results and the brief discussions about the hydrogen absorption and disorption behaviors of the hydrogen storage tank, it is suggested that the behaviors of hydrogen charging and discharging could be controlled by adjusting the operating parameters and the reactor design parameters.

• 마이크로전자및패키징학회지
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• 제17권4호
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• pp.83-88
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• 2010

복합전기도금은 도금 중 반응성이 없는 물질을 첨가하여 도금층 내부에 함께 존재하도록 함으로써 이루어진다. 퍼멀로이는 철과 니켈의 합금을 말하는 것으로써 높은 투자율를 나타내기 때문에 산업 여러 분야에 응용된다. 복합도금을 통해 제품의 미세경도를 향상시킬 수 있으며 이는 제품의 수명과 연관된다. 하지만 실리카 나노분말 표면의 수산화기는 표면을 수분에 취약하게 만들고 이는 나노분말의 응집을 발생시켜 균일한 도금층의 형성을 어렵게 하는 요인이 된다. 본 연구에서는 실리카 나노분말의 응집을 줄이기 위하여 첨가제의 변화, 초음파 처리 시간의 변화를 살펴보았다. 초음파 처리시간의 증가시 입자의 분산효과가 좋았고 조성의 변화가 발생하였다. 첨가제에 따라 표면 형상과 공석되는 실리카 나노입자의 함량 차이가 나타났다. 염기성 도금용액에서 sodium lauryl sulfate를 사용하였을 경우 표면이 매끄럽고 공석되는 실리카 나노분말의 양도 높았다.

• 방사성폐기물학회지
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• 제3권1호
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• pp.31-40
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• 2005

발전소 내 방사화 부식생성물의 대부분을 차지하고 있는 니켈 페라이트계 부식생성물을 모사 발생시키기 위한 고온 고압용 장치를 제작하여 연구를 수행하였다. 배관형 포집기를 이용한 부식생성물 발생장치로부터 방사화 부식생성물과 가장 유사한 부식생성물을 얻을 수 있었다. 발전소에서 입자성 부식생성물이 발생되는 원리인 온도에 따른 용해도 차이를 구현하기 위하여 270$\^{circ}$C에서 부식반응이 일어나 상대적으로 높은 온도를 가진 포집용 장치에 부식생성물이 포집되도록 장치를 제작하였으며 , 발생된 부식생성물은 주사전자현미경 관찰과 EDAX를 통한 조성분석으로 그 특성을 관찰하였다. 부식생성물은 포집 된 위치 에 따라서 침상 형태의 산화물과 결정 형태의 산화물로 나뉘었으며, 조성 분석 결과 결정 형태의 부식생성물이 니켈 페라이트로서 발전소에서 발생되는 입자성 부식생성물과 유사한 것을 알 수 있었다.

• 한국분말재료학회지
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• 제22권3호
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• pp.197-202
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• 2015

In this study, porous stainless steel (STS316L) sintered body was fabricated by powder metallurgy method and its properties such as porosity, compressive yield strength, hardness, and permeability were evaluated. 67.5Fe-17Cr- 13Ni-2.5Mo (wt%) powder was produced by a water atomization. The atomized powder was classified into size with under $45{\mu}m$ and over $180{\mu}m$, and then they were compacted with various pressures and sintered at $1210^{\circ}C$ for 1 h in a vacuum atmosphere. The porosities of sintered bodies could be obtained in range of 20~53% by controlling the compaction pressure. Compressive yield strength and hardness were achieved up to 268 MPa and 94 Shore D, respectively. Air permeability was obtained up to $79l/min{\cdot}cm^2$. As a result, mechanical properties and air permeability of the optimized porous body having a porosity of 25~40% were very superior to that of Al alloy.

• 한국재료학회지
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• 제15권3호
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• pp.155-160
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• 2005

The electrolytic reduction of spent oxide fuel involves the liberation of oxygen in a molten LiCl electrolyte, which results in a chemically aggressive environment that is very corrosive fir typical structural materials. So, it is essential to choose the optimum material f3r the process equipment handling molten salt. In this study, the corrosion behavior of Al-Y coated Haynes 263 in a molten salt of $LiCl-Li_2O$ under oxidation atmosphere was investigated at $650^{\circ}C$ for $72\~168$ hours. The corrosion rate of Al-Y coated Haynes 263 was low while that of bare Haynes 263 was high in a molten salt of $LiCl-Li_2O$. Al-Y coated Haynes 263 improved the corrosion resistance better than bare Haynes 263 alloy. An Al oxide layer acts as a protective film which Prohibits Penetration of oxygen. Corrosion Products were formed $Li(Ni,Co)O_2$ and $LiTiO_2$ on bare Haynes 263, but $LiAlO_2,\;Li_5Fe_5O_8\;and\;LiTiO_2$ on Al-Y coated Haynes 263.

• 한국수소및신에너지학회논문집
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• 제31권5호
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• pp.419-428
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• 2020

The kinetics of direct methanation over activated charcoal-supported molybdenum catalyst at 30 bar was studied in a cylindrical fixed-bed reactor. When the temperature was not higher than 400℃, the CO conversion increased with increasing temperature according to the Arrhenius law of reaction kinetics. While XRD and Raman analysis showed that Mo was present as Mo oxides after reduction or methanation, TEM and XPS analysis showed that Mo₂C was formed after methanation depending on the loading of Mo precursor. When the temperature was as high as 500℃, the CO conversion was dependent not only on the Arrhenius law but also on the catalyzed reaction by nanoparticles, which came off from the reactor and thermocouple by metal dusting. These nanoparticles were made of Ni, Fe, Cr and alloy, and attributed to the formation of carbon deposit on the wall of the reactor and on the surface of the thermocouple. The carbon deposit consisted of amorphous and disordered carbon filaments.

• 한국전기전자재료학회논문지
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• 제22권4호
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• pp.342-349
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• 2009

This study investigated the growth characteristics of carbon nanotubes (CNTs) by changing a period of annealing time and a $C_{2}H_{2}/H_2$ flow ratio at temperature as low as $450^{\circ}C$ with inductively coupled plasma chemical vapor deposition. The 1-nm-thick Fe-Ni-Co alloy thin film served as a catalyst layer for the growth of CNTs, which was thermally evaporated on the 15-nm-thick Al underlayer deposited on the 50-nm-thick Ti diffusion barrier. The annealing at low temperature of $450^{\circ}C$ brought about almost no granulation of the catalyst layer, and the CNT growth was not affected by a period of annealing time. A study of changing the flow rate of $C_{2}H_{2}$ and $H_2$ showed that as the ratio of the $C_{2}H_{2}$ flow rate to the $H_2$ flow rate was lowered, the CNTs were grown to be longer With further decreasing the flow ratio, the length of CNTs reached the maximum and then became shorter. Under the optimized gas flow rates, we successfully synthesized CNTs with a uniform length over a 4-inch Si wafer at $450^{\circ}C$.

• 전자공학회논문지
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• 제54권3호
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• pp.131-137
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• 2017

네트워크 기반의 휴대용 전자 제품의 시장 성장으로 전기기기들은 더욱 소형화 되고 있는 추세이고 내부 부품간의 거리가 가까워져 회로 단락의 위험이 높아지고 있다. 회로의 단락 상황에서 유입되는 높은 과전류로 부터 폭발이나 화재 없이 전자기기를 안전하게 보호하기 위해서는 차단용량이 높은 밀폐형 카트리지 퓨즈를 적용해야 하지만 제품의 소형화 추세에 따른 공간의 문제로 해당 퓨즈의 적용이 불가능한 실정이다. 이를 해결하기 위해서 화학적 결합으로 퓨즈 가용체를 보호하는 밀폐형 퓨즈보다 공기의 유입이 자유로울 뿐만 아니라 물리적 결합으로 퓨즈링크를 보호하는 반밀폐형 초소형 퓨즈가 적용되는 것이 적합하지만 높은 차단용량 특성을 구현하는데 한계가 있다. 이에 본 논문에서는 상대적으로 공간을 적게 차지하면서 높은 차단용량을 갖는 반밀폐형 초소형 퓨즈를 위한 퓨즈 가용체 합금과 퓨즈링크의 설계 기술을 통하여 회로의 단락 상황에서 안전성을 확보하였다.

• 대한기계학회논문집
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• 제12권5호
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• pp.1083-1091
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• 1988

본 연구에서는 위의 두번째 연구동향과 맥락을 같이하는 것으로서 스테인리스 강(SUS304)에 대한 진공브레이징 연구 및 탄소강의 진공 브레이징에 대한 연구결과들 을 토대로 하여 SUS304와 탄소강과의 진공브레이징 현상을 연구하였는데 특히 모재의 탄소함유량, 브레이징시간 및 접합부 틈새(joint clearance)등에 따라 접합부에 나타 나는 여러 금속학적 현상의 규명 및 접합강도(joint strength)에 대해 변수들이 미치 는 영향을 연구 하였다.

• 한국표면공학회지
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• 제55권6호
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• pp.448-459
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• 2022

Generally, steel is the most commonly used in the industry because of good strength, processability and cost-effectiveness. Steel can be surface-treated such as coating or used as an alloy by adding elements such as Cr, Ni, Zr, and Al to increase corrosion resistance. However, even if steel is used in same environment corrosion resistance is sharply lowered when it is exposed to a high temperature for a fixed or extended period of time due to an overload or other factors. In particular, the use of hot-dip aluminized plated steel, which is used in high-temperature atmospheres, is increasing due to the surface Al₂O₃ oxide film. This steel necessitates an urgent solution as issues of corrosion resistance limitations often appear. It is an important issue that not only cause analysis but also the research for the surface treatment method that can be solved. Thus, in this study, Cr in which it is expected to be effective in corrosion resistance and heat resistance attempted to deposit on hot dip aluminized plated steel with PVD sputtering. And it was possible to present the surface treatment application of various types of industrial equipment exposed to high temperature and basic design guidelines for use by confirming the corrosion resistance of hot dip Al-Si plated steel with Cr film deposited at high temperature.